Casing treatments in the casing walls surrounding compressor rotors in gas turbine engines may be used to improve the surge margin. A common type of casing treatment includes the formation of circumferential grooves in the inner surface of the casing wall. The grooves may allow the flow of air to pass over the blade tip, which in turn may enable momentum exchange to energize tip flow as stall is approached. However, the grooves may create losses in the compressor that may impact compressor efficiency.